Alton mentions squiring for Ser Jaime at the tourney during [[Willem Frey]]'s wedding. He says that he was such a minor relation to the Lannisters that they were put at a table so far away he could barely see the bride and that his father was furious at Alton's volunteering to be a replacement squire as he might embarrass their lesser branch of the family before of the major one. At first Jaime doesn't remember until reminded that his squire Brian had become so sick he threw up on his own horse. He then remembers that Alton had been a much better squire than Jaime himself had been and shares his experience of squiring for [[Barristan Selmy]] when he was 16 fighting the [[Kingswood Brotherhood]].

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Alton mentions squiring for Ser Jaime at the tourney during [[Willem Frey]]'s wedding. He says that he was such a minor relation to the Lannisters that they were put at a table so far away he could barely see the bride and that his father was furious at Alton's volunteering to be a replacement squire as he might embarrass their lesser branch of the family before the major one. At first Jaime doesn't remember until reminded that his squire Brian had become so sick he threw up on his own horse. He then remembers that Alton had been a much better squire than Jaime himself had been and shares his experience of squiring for [[Barristan Selmy]] when he was 16 fighting the [[Kingswood Brotherhood]].

Soon after news of King Joffrey Baratheon's bastardhood reach the Northern camp, Robb Stark tells Ser Alton his terms for a peace with the Iron Throne, and then sends him to King's Landing to deliver them to the Queen Regent. Ser Alton remarks that the Robb's demand for the return of Sansa and Arya as well as Ned Stark's bones and the remains of all the Stark household, is an honorable request, but expresses doubt and surprise when Robb also demands that the independence of the North and Riverlands be respected. He also tries to correct Robb when he refers to Joffrey as a Lannister.[1]

Ser Alton delivers the Stark peace terms, which are rejected by Queen Cersei. Cersei sends him back with the Iron Throne's reply. Cersei also asks him to tell Jaime that he has not been forgotten. Tyrion wishes Alton a safe journey.[2]

He returns to the Westerlands to informs Robb of Cersei's response, and Robb asks that he return to his old pen but the prisoners are far too many that they have occupied it. Alton is placed in the Kingslayer's cell, until a new pen can be built. He tells Jaime that his mother is Cynda Lannister at which Jaime, not knowing who that is, asks if she is the fat one.

Alton Lannister imprisoned

Alton mentions squiring for Ser Jaime at the tourney during Willem Frey's wedding. He says that he was such a minor relation to the Lannisters that they were put at a table so far away he could barely see the bride and that his father was furious at Alton's volunteering to be a replacement squire as he might embarrass their lesser branch of the family before the major one. At first Jaime doesn't remember until reminded that his squire Brian had become so sick he threw up on his own horse. He then remembers that Alton had been a much better squire than Jaime himself had been and shares his experience of squiring for Barristan Selmy when he was 16 fighting the Kingswood Brotherhood.

Alton asks if Jaime has ever thought of escaping imprisonment, when Jaime replies that he has a plan, Alton agrees to help and gets close to hear what he is to do. Jaime whispers to him the one thing he has to do is to die, then headbutts him and beats him repeatedly with his shackles. Torrhen Karstark enters the cell to check the convulsing Alton, allowing Jaime to get behind him and strangle him with his chains. Getting the key from his belt, he frees himself from the chains and escapes from the cell.[3]

In the books

In the A Song of Ice and Fire books, there is no character by this name. The character Cleos Frey has the role of being a captive of House Stark and delivering terms to House Lannister. Cleos Frey is the son of Ser Emmon Frey, Walder Frey's second son, and Genna Lannister, the only sister of Tywin Lannister. His name appears to have been changed so that TV viewers would not be confused that he is on the Lannisters' side, despite House Frey officially declaring for Robb Stark.

While Alton does serve in the same role as Cleos Frey in the books, it is later made clear that he is not the son of Genna Lannister as he mentions his mother is Cynda Lannister, whom Jaime has difficulty remembering. Thus "Alton Lannister" isn't as important a familial relation as Cleos Frey is; he is not Lord Tywin's nephew and Jaime's first cousin the way Cleos is in the books.

Besides being the courier in negotiating peace terms, Cleos Frey also has in common with Alton Lannister that he takes part in the two escape attempts of Jaime Lannister. When Tyrion Lannister sends Cleos back with Eddard's bones and the Lannister terms for peace to Robb Stark, there are four men mixed in with the other escorting soldiers that are there to break Jaime out. One does impressions and imitates Edmure Tully ordering the gate raised, but the real Edmure was returning from a brothel in town and the escape is foiled. Cleos swore he knew nothing about the escape plan, but Edmure did not believe him and ordered to lock him in the cell where Jaime was previously kept, claiming that Cleos is "half Lannister, half Frey, and all liar". When Cleos was brought before Catelyn, he fearfully swore he had no idea about Tyrion's plan. Catelyn Stark did not care much if he was telling the truth or not, and demanded to know what peace terms the Lannisters offered them. After Cleos told her the terms he brought, Catelyn asked about her daughters. He answered evasively, but after Catelyn threatened to hang him - he told her the truth that he only saw Sansa.

When Brienne and Jaime left, it was Catelyn Stark who ordered the gate raised as she was sending Cleos Frey back to King's Landing with new terms, with Jaime Lannister hidden in the bottom of the boat. Cleos Frey left with Brienne and Jaime, headed for King's Landing.

On the way to King's Landing, they were attacked by archer outlaws. Cleos and his horse were shot several times. He fell from the saddle, but his foot was caught in the stirrup, and his horse dragged him away, his head bouncing against the ground. As a result, Cleos' skull was smashed. Jaime did not express any sorrow for his cousin's death, but instead meant to strip him of his clothes and weapon. He used Cleos' sword to attack Brienne (not Brienne's sword).

Jaime has a very negative opinion on Cleos, being a coward and flatterer. He mused that "Ser Cleos looked like a weasel, fought like a goose, and had the courage of an especially brave ewe".